Ducts or pipes of relatively large diameter which are mounted in the engine compartments of motor vehicles often need to be provided with shaping devices enabling their section shape to be modified, in particular for flattening purposes, and/or enabling their direction to be modified, e.g. in order to pass round an obstacle, with the need of such devices being due essentially to the lack of space available within the engine compartment, thus requiring certain portions of ducts or of pipes to be bent and flattened in order to make it possible to house them in the desired locations.
At present, such shaping devices are made of rigid plastics material overmolded on the ducts or pipes, thereby giving rise to problems that can be complex. Solid cores need to be placed inside the ducts during overmolding of the above-specified devices and they can be very difficult to remove after overmolding.